The present invention relates to an insect pest eradication system comprised of a non-lethal knockout agent and an insecticide. The present invention also relates to a method for eradicating insects, particularly those found in earthen colonies, by treating the colony with a non-lethal knockout agent, such as trans-dichloroethylene, in combination with a suitable insecticide for the targeted insects.
Non-indigenous insect pest infestations present a significant problem to homeowners, landowners, livestock and vegetation in the warmer regions of the United States. For example, the Red Fire Ant (fire ant) proliferates across the South and has more recently begun to invade parts of Southern California. The fire ant lives in colonies comprised of at least several thousands of individuals. Some colonies have been known to contain up to about 500,000 or more ants. When their dirt mounds are disturbed, the ants swarm upon the invader delivering relentless and extremely painful stings. In humans, the stings cause itching welts that may last for many days. Scratching the wounds may lead to infection and some persons may even suffer severe allergic reactions. Small children unfamiliar with the habits of the fire ant are particularly susceptible to attack. The fire ant provides an even greater danger to livestock. Fire ant mounds dot most pastures in the Southern United States and cattle frequently suffer from ant attacks. Abundant fire ant stings may, in fact, kill calves. Vegetation is also susceptible to depletion by foraging fire ants. Furthermore, fire ants that have infested agricultural fields pose a threat to humans harvesting crops. Damage due to fire ants is estimated at tens of millions of dollars annually.
A common method currently in use for controlling fire ants involves the application of granules coated with a water-soluble poison directly onto a fire ant mound, and then gently dousing the mound with water, so that the poisonous coating is dissolved and carried into the colony. One brand of such product, Spectracide(copyright), which is comprised of Diazinon(copyright) (C12H21N2O3PS), advertises that it will kill fire ants within 24 hours. Unfortunately, the technique is somewhat ineffective. Individual insects may be observed moving actively about the targeted colony when the insecticide granules and/or water are applied. Furthermore, new fire ant colonies, presumably individuals and an unharmed queen from the targeted colony, have been observed to form in the immediate vicinity of the original mound within 12 hours of the treatment.
Another common technique currently employed for controlling the fire ant problem involves the use of xe2x80x9cbaitingxe2x80x9d systems, wherein a poison is implanted into a fire ant food source, which is carried back into the fire ant colony by worker ants. This technique, while considered environmentally advantageous, has the distinct disadvantage of being relatively slow acting when compared to direct application of insecticide to the fire ant colony. For example, one of the faster-acting xe2x80x9cbaitsxe2x80x9d is Amdro(copyright), which is comprised of hydramethylnon and has the chemical name tetrahydro-5,5-dimethyl-2(1H)-pyrimidinone {3-{4-(trifluoromethyl) phenyl}-1-{2-{4-trifluoromethyl) phenyl}ethenyl}-2-propenyl-idene}hydrazone. When it is broadcast it is reported to have a maximum 80%-90% effectiveness rating in 3 to 8 weeks. In such time, it is highly probable that the rapidly propagating fire ant would establish new colonies not far from baited sites. Furthermore, a xe2x80x9cbaitingxe2x80x9d system is always subject to the foraging whimsy of the individual fire ant. When other food sources are accessible fire ants may not even seize the bait. In addition, these baits are always subject to dilution and/or dispersion by rains and flooding, potentially rendering them ineffective in targeted areas.
Certain chlorinated hydrocarbons have been used in the past for controlling insect pests such as the fire ant. U.S. Pat. No. 5,104,659 to Fishbein discloses a wide variety of insecticides, including xe2x80x9cchlorinated hydrocarbons.xe2x80x9d U.S. Pat. No. 5,897,859 to Vander Meer discloses that fire ant problems in agricultural areas were largely suppressed xe2x80x9cthrough the wide scale use of residual chlorinated hydrocarbon insecticides from 1950 to 1970,xe2x80x9d but that use of these xe2x80x9chighly effective insecticidesxe2x80x9d largely ceased because of environmental concerns. U.S. Pat. No 4,626,528 to McHenry discloses that xe2x80x9cthe only truly successful toxicant for the control of fire ants and termites has been Mirex, a chlorinated hydrocarbonxe2x80x9d but that xe2x80x9cthis material has been withdrawn from use because of concerns over its toxicity in certain animals and its unusual stability in the environment.xe2x80x9d
Furthermore, chlorinated compounds have been used as carriers and solvents in insecticides. For example U.S. Pat. No. 5,278,163 to Ogura, et al. discloses that chlorinated hydrocarbons may be used as carriers for pesticidal compounds. U.S. Pat. No. 3,678,168 to Grier specifies that chlorinated hydrocarbons such as xe2x80x9cchloroform, carbon tetrachloride and tetrachloroethylenexe2x80x9d may serve as suitable carriers for pesticidal compounds. Also, U.S. Pat. No. 5,620,678 to Burke discloses that xe2x80x9c(h)alogenated solvents, such as methylene chloride and 1,1,1-trichloroethane are common carriers, diluents and solvents for aerosol spraysxe2x80x9d used to eradicate crawling and flying insect pests, but that these applications xe2x80x9chave been restricted due to health and environmental concerns.xe2x80x9d All of the above mentioned patents are incorporated herein by reference.
While there are many commercially available insecticide systems for killing insects, particularly those that colonize in great numbers, there is a need in the art for systems that are more effective for killing substantially all insects in a colony.
An insecticide delivery system comprising an effective amount of a non-lethal knockout agent and an effective amount of an insecticide.
In a preferred embodiment the insecticide delivery system of claim 1 wherein the knockout agent is selected from the group consisting of cis-dichloroethylene, trans-dichloroethylene, trichloroacetaldhyde, trichloroacetaldhyde hydrate, chloral, and chloral hydrate.
In another preferred embodiment the insect is a fire ant, the insecticide is selected from Diazinon(copyright) and hydramethylnon, and the knockout agent is trans-dichloroethylene.
In still another preferred embodiment the knockout agent and the insecticide are blended together and applied to the insect infestation together.